How Python implements Port forwarders

The examples in this article describe how Python implements port forwarders. Share to everyone for your reference. Specific as follows:

The following Python code implements the port forwarder, which supports UDP port forwarding

Because the work requires a port forwarder, and requires support for TCP and UDP protocols. On the internet for a long time, but no favorite. So I wrote one of my own. This transponder is based on an example of Python cookbook, the original example only supports the TCP protocol, I have added the support of the UDP protocol, the program does not write well, but it does work!

The portmap.py code is as follows:

The code is as follows:

#-*-coding:utf-8-*-
'''
Created on 2012-5-8
@author: QH
'''
Import time,socket,threading
def log (Strlog):
Strs=time.strftime ("%y-%m-%d%h:%m:%s")
Print strs+ "," +strlog
Class Pipethread (threading. Thread):
'''
Classdocs
'''
def __init__ (Self,source,sink):
'''
Constructor
'''
Threading. Thread.__init__ (self)
Self.source=source
Self.sink=sink
Log ("New Pipe create:%s->%s"% (Self.source.getpeername (), Self.sink.getpeername ()))
def run (self):
While True:
Try
DATA=SELF.SOURCE.RECV (1024)
If not data:break
Self.sink.send (data)
Except Exception, ex:
Log ("redirect error:" +str (ex))
Break
Self.source.close ()
Self.sink.close ()
Class Portmap (threading. Thread):
def __init__ (self,port,newhost,newport,local_ip= "):
Threading. Thread.__init__ (self)
Self.newhost=newhost
Self.newport=newport
Self.port=port
Self.local_ip=local_ip
Self.sock=none
Self.sock=socket.socket (Socket.af_inet,socket. SOCK_STREAM)
Self.sock.bind ((Self.local_ip,port))
Self.sock.listen (5)
Log ("Start listen protocol:%s,port:%d"% (' TCP ', port)
def run (self):
While True:
Fwd=none
Newsock=none
Newsock,address=self.sock.accept ()
Log ("New connection->protocol:%s,local port:%d,remote address:%s"% (' TCP ', Self.port,address[0])
Fwd=socket.socket (Socket.af_inet,socket. SOCK_STREAM)
Try
Fwd.connect ((Self.newhost,self.newport))
Except Exception, ex:
Log ("Connet newhost Error:" +str (ex))
Break
P1=pipethread (Newsock,fwd,self.protocol)
P1.start ()
P2=pipethread (Fwd,newsock,self.protocol)
P2.start ()
Class PIPETHREADUDP (threading. Thread):
def __init__ (Self,connection,connectiontable,table_lock):
Threading. Thread.__init__ (self)
Self.connection=connection
Self.connectiontable=connectiontable
Self.table_lock=table_lock
Log (' new thread for New Connction ')
def run (self):
While True:
Try
data,addr=self.connection[' socket '].recvfrom (4096)
#log (' recv from addr '%s '% str (addr))
Except Exception, ex:
Log ("Recvfrom error:" +str (ex))
Break
Try
self.connection[' Lock '].acquire ()
self.connection[' ServerSocket '].sendto (data,self.connection[' address ')
#log (' sendto address:%s '% str (self.connection[' address '))
Except Exception, ex:
Log ("SendTo Error:" +str (ex))
Break
finally:self.connection[' Lock '].release ()
self.connection[' time ']=time.time ()
self.connection[' socket '].close ()
Log ("Thread Exit For:%s"% str (self.connection[' address '))
Self.table_lock.acquire ()
Self.connectionTable.pop (self.connection[' address ')
Self.table_lock.release ()
Log (' Release UDP connection for timeout:%s '% str (self.connection[' address '))
Class PORTMAPUDP (threading. Thread):
def __init__ (self,port,newhost,newport,local_ip= "):
Threading. Thread.__init__ (self)
Self.newhost=newhost
Self.newport=newport
Self.port=port
Self.local_ip=local_ip
Self.sock=socket.socket (Socket.af_inet,socket. SOCK_DGRAM)
Self.sock.bind ((Self.local_ip,port))
self.connetctable={}
Self.port_lock=threading. Lock ()
Self.table_lock=threading. Lock ()
self.timeout=300
#ScanUDP (Self.connetctable,self.table_lock). Start ()
Log (' UDP port redirect run->local_ip:%s,local_port:%d,remote_ip:%s,remote_port:%d '% (Local_ip,port,newhost, Newport))
def run (self):
While True:
Data,addr=self.sock.recvfrom (4096)
Connection=none
Newsock=none
Self.table_lock.acquire ()
Connection=self.connetctable.get (addr)
Newconn=false
If connection is None:
connection={}
connection[' Address ']=addr
Newsock=socket.socket (Socket.af_inet,socket. SOCK_DGRAM)
Newsock.settimeout (Self.timeout)
connection[' socket ']=newsock
connection[' Lock ']=self.port_lock
connection[' ServerSocket ']=self.sock
connection[' time ']=time.time ()
Newconn=true
Log (' new connection:%s '% str (addr))
Self.table_lock.release ()
Try
connection[' socket '].sendto (data, (Self.newhost,self.newport))
Except Exception, ex:
Log ("SendTo Error:" +str (ex))
#break
If Newconn:
Self.connetctable[addr]=connection
T1=PIPETHREADUDP (Connection,self.connetctable,self.table_lock)
T1.start ()
Log (' main thread exit ')
For key in Self.connetcTable.keys ():
self.connetctable[key][' socket '].close ()
If __name__== ' __main__ ':
MYP=PORTMAPUDP (10061, ' 10.0.1.29 ', 161)
Myp.start ()
#myp. __stop ()

Hopefully this article will help you with Python programming.

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